Muscles Crossing Hip and Knee Joints: Movements of the Thigh and Leg Most anterior compartment muscles of the hip and thigh flex the femur at the hip and extend the leg at the knee Posterior compartment muscles of the hip and thigh extend the thigh and flex the leg The medial compartment muscles all adduct the thigh These three groups are enclosed by the fascia lata
Movements of the Thigh at the Hip The ball-and-socket hip joint permits flexion, extension, abduction, adduction, circumduction, and rotation Iliopsoas: primer mover for flexing thigh Psoas major: Iliacus: Sartorius: flexes, abducts, and laterally rotates thigh All muscles below press the thighs together (adductors). When strained, they result in what is commonly called a Pulled Groin. Adductors: Pectineus: Gracilis: Magnus Longus brevis
Knee Extension Anterior Muscles: Quadriceps femoris: Rectus femoris: Extends the knee Vastus lateralis: Vastus medialis: Vastus intermedius: Tensor fasciae latae: flexes and abducts the thigh Posterior Muscles: Gluteus maximus: major extensor of thigh, most effective when thigh is flexed Gluteus medius: abducts and medially rotates thigh. Most important in walking. Holds pelvis in abduction while the swinging limb swings forward. Gluteus mimimus:
Movements of the Thigh at the Hip: Flexion and Extension Figure 10.19a c
Movements of the Thigh at the Hip: Other Movements Figure 10.20a
Movements of the Thigh at the Hip: Other Movements Lateral rotators: Piriformis: rotates and extends thigh laterally Obturator internus: Gemellus: Quadratus femoris: Rotates thigh laterally Hamstrings: prime movers of thigh extension & knee flexion If knee is fixed (extended) they promote hip extension If hip is extended, they promote knee flexion Biceps femoris: extends thigh & flexes knee Semitendinosus: Semi membranosus:
Movements of the Thigh at the Hip: Other Movements Figure 10.20b c
Movements of the Knee Joint The sole extensor of the knee is the quadriceps femoris The hamstring muscles flex the knee, and are antagonists to the quadriceps femoris Figure 10.19a
Fascia of the Leg A deep fascia of the leg is continuous with the fascia lata This fascia segregates the leg into three compartments: anterior, lateral, and posterior Figure 10.22a
Fascia of Leg Deep fascia of leg binds leg muscles tightly preventing swelling of muscles during exercise and aiding venous return. Distally, the fascia thickens and forms the flexor, extensor, and fibular retinaculae that holds the ankle tendons in place where they run to the foot
Muscles of the Leg: Movements Various leg muscles produce the following movements at the: Ankle dorsiflexion and plantar flexion Intertarsal joints inversion and eversion of the foot Toes flexion and extension
Muscles of the Leg Anterior Lateral Posterior Tibialis anterior: prime mover of dorsiflexion, supports longitudinal arch of foot, inverts foot Extensor digitorum longus: prime mover of toe extension Fibularis (peroneus) tertius: dorsiflexes, everts foot Extensor hallucis longus: extends great toe, dorsiflexes foot Fibularis (peroneus) longus: everts foot/ plantar flexes foot Fibularis (peroneus) brevis: Gastocnemius: plantar flexes foot when knee is extended Soleus: Plantaris: and assists in knee flexion
Muscles of the Leg Deep Muscles: Popliteus: flexes, rotates leg medially to unlock extended knee Flexor digitorum longus: inverts & plantar flexes foot Flexor hallucis longus: and flexes great toe, it is the push off muscle during walking Tibialis posterior: prime mover of foot inversion and plantar flexes foot
Muscles of the Anterior Compartment These muscles are the primary toe extensors and ankle dorsiflexors They include the tibialis anterior, extensor digitorum longus, extensor hallucis longus, and fibularis tertius Figure 10.21a
Muscles of the Anterior Compartment Figure 10.21b d
Muscles of the Lateral Compartment These muscles plantar flex and evert the foot They include the fibularis longus and fibularis brevis muscles Figure 10.22a
Muscles of the Lateral Compartment Figure 10.22b, c
Muscles of the Posterior Compartment These muscles primarily flex the foot and the toes They include the gastrocnemius, soleus, tibialis posterior, flexor digitorum longus, and flexor hallucis longus Figure 10.23a
Muscles of the Posterior Compartment Figure 10.23b, c
Muscles of the Posterior Compartment Figure 10.23d f
Muscle Actions of the Thigh: Summary Thigh muscles: Flex and extend the thigh (posterior compartment) Extend the leg (anterior compartment) Adduct the thigh (medial compartment)
Muscle Actions of the Thigh: Summary Flexes thigh Figure 10.24a
Muscle Actions of the Leg: Summary Leg muscles: Plantar flex and evert the foot (lateral compartment) Plantar flex the foot and flex the toes (posterior compartment) Dorsiflex the foot and extend the toes (anterior compartment)
Muscle Actions of the Leg: Summary Figure 10.24b
Intrinsic Muscles of the Foot: Toe Movement and Arch Support These muscles help flex, extend, abduct, and adduct the toes In addition, along with some leg tendons, they support the arch of the foot There is a single dorsal foot muscle, the extensor digitorum brevis, which extends the toes The plantar muscles occur in four layers
Intrinsic Muscles of the Foot: Toe Movement and Arch Support Sole of foot, 1 st layer: Extensor digitorum brevis: extends toes Flexor digitorum brevis: flex toes (synergist) Abductor hallucis: abducts great toe Abductor digiti minimi: abducts/flexes little toe Sole of foot, 2 nd layer: Flexor accessorius: straightens oblique pull of flexor digitorum longus Lumbricals: flexes and extends toes Sole of foot, 3 rd layer: Flexor hallucis brevis: flexes great toe Adductor hallucis: weak adductor of great toe, maintains transverse arch Flexor digiti minimi brevis: flexes little toe Sole of foot, 4 th layer: Dorsal & plantar interossi: abductor and adductor of toes, respectively
Plantar Muscles: First Layer (Superficial) Superficial muscles of the plantar aspect of the foot These muscles are similar to the corresponding muscles of the hand Figure 10.25a
Plantar Muscles: Second Layer Figure 10.25b
Plantar Muscles: Third Layer Figure 10.25d
Plantar Muscles: Fourth Layer Figure 10.25e f